Window canister assembly



Nov. 22, 1960 w. J. WISWESSER WINDOW CANISTER ASSEMBLY Filed July 2, 195a INVENTOR. William J Mswesselr WINDOW CANISTER ASSEMBLY William J. Wiswesser, Reading, Pa., assignor to The Electric Storage Battery Co., Philadelphia, Pa.

Filed luly 2, 1958, SB!- No. 746,213

2 Claims. (21. 23-284) This invention relates to a window assembly for gas mask canisters and, more particularly, to a prefabricated, moisture-detecting or vapor-detecting window assembly that can be easily and quickly soldered in the wall of the canister.

In the past, various means have been used to denote the moisture content or life of a gas mask canister. However, these means have not proved entirely satisfactory for various reasons, such as the generally complicated devices required embodying screw threaded connections and the like and lack of complete reliability because of imperfect connections and the like.

An object of my invention is to provide a novel canister Window assembly for detecting moisture in gas masks which is devoid of the above named disadvantages and which is of relatively simple and inexpensive construction.

Another object of my invention is to provide a canister window assembly in the form of a prefabricated unit encased in a seamless cup, which cup may be easily and quickly mounted in an air-tight manner in the wall of the canister by a single soldering connection. The window assembly may incorporate moisture-detecting papers or vapor-detecting papers, or may be free of any such papers, in order to observe a color change in an indicatortinted layer of canister chemical.

Other objects and advantages of my invention will become more apparent from a study of the following description taken with the accompanying drawing wherein:

Fig. 1 is an elevational view showing, in dotted outline, a gas mask and flexible tube, and in full lines, a canister which has installed in its wall a canister Window assembly embodying the principles of my invention;

Fig. 2 is a transverse cross-sectional view taken along line II--II of Fig. 1;

Fig. 3 isa side view of the seamless cup, shown in Figs. 1 and 2, which contains a complete assembly including moisture or vapor indicating paper in accordance with the principles of the present invention;

Fig. 4 is a front elevational view of the canister window assembly shown in Fig. 3;

Figs. 5, 6, 7, 8, 9, and denote various parts included in the canister window assembly and shown in assembled relationship in Fig. 2; and

Fig. 11 shows a preferred modification of the canister window assembly mounting.

Referring more particularly to the drawing, numeral 1 denotes a gas mask face piece of any well-known construction, which face piece is connected by means of a flexible tubing 2, such as corrugated tubing, to a gas mask canister 3 filled with any suitable gas filtering material 3a, such as hopcalite.

The front wall of the canister is provided with a circular hole for receiving a cup subassembly. The container or cup 4 is a seamless cylinder having the bottom beaded outwardly to form a soldering lip 4a, and punched United States Patent out to form a circular hole; and having the top edge 4b crimped radially inwardly after filling, to form an airtight connection with the top gasket. The cup-filling sequence may start with the inner gasket 5 if the finished cup is inserted from the inside of the canister, as shown in Fig. 2, or with the outer gasket 9 if the finished cup is inserted from the outside of the canister, as shown in Fig. 11.

There is provided between these gaskets a moisture or vapor indicating assembly comprising a backing disc 6 of cardboard, blotting paper or other suitable absorbent material against which is placed a pair of half discs 7a and 7b. Half disc 7a may constitute a reference paper of permanent color, such as a light-fast or permanent blue-violet tint. The other half disc 7b may constitute a moisture or vapor indicating paper, the color of which changes in accordance with moisture or vapor changes, such as a cobalt bromide indicator made from approximately 1% aqueous solution. When both colors match, the service life of the canister is spent. The half discs are visible through the disc-shaped window which rests against gasket 9. An important result obtained by the useof cobalt bromide, instead of cobalt chloride, is that it will provide a color change which more nearly matches or corresponds to the useful life of hopcalite from the standpoint of moisture absorption or service life of the canister for protection against carbon monoxide.

It will be noted that cup 4 is a seamless cup and may be fabricated in the form of a gas-tight assembly as shown. In fact, the cup assembly may be tested for gas-tightness even before insertion in the hole of the canister. After the seamless cup canister assembly has been completed and tetsted, it is inserted in the hole in the front or other wall of the canister and a soldered connection is formed outside of the inturned marginal portion 3b, so as to constitute the sole connection, and an air-tight one, between the seamless cup 4 and the wall of the canister 3. Thus, the present construction avoids the necessity of threading or the necessity of a plurality of soldering connections as commonly necessary in devices of a similar character.

The canister window assembly described above is found to be gas-tight even after long use and is able to withstand momentary temperatures approximating 500 F.

Fig. 11 shows the preferred manner of mounting the seamless cup assembly, wherein the cup is inverted as compared to the modification shown in Fig. 2. Other identical elements are referred to by the same reference numerals.

Thus it will be seen that I have provided an efiicient canister window assembly for gas masks, which assembly contains moisture or vapor-indicating colored paper and is adapted to be completely contained within a seamless cup, and which cup is very easily installed in the canister by a single soldered connection to insure gas-tightness: as well as a rigid mounting; furthermore, I have provided a canister window assembly which is easily made gastight and is completely contained in a prefabricated unit within a seamless cup and may be pre-tested for gas tightness so that upon installation in a canister, complete assurance is had that the gasrnask assembly is gas-tight. 1'

While I have illustrated and described a single specific embodiment of my invention, it will be understood that I this is by way of illustration only, and that various changes and modifications may be made within the con of the,

templation of my invention and-within the scope following claims.

I claimz 3 peripheral portion, a seamless, metallic, substantially cylindrical container of diameter slightly smaller than that of said hole, snugly fitted in said hole, said container having, on one side, a radially outwardly flared, peripheral head portion having a tapered portion complementin and snugly seated in said inwardly bent peripheral portion and being soldered thereto externally of said canister, said head portion terminating in a radially inwardly bent, annular ledge portion, the other side of said container also having a radially inwardly bent, annular ledge portion, a pair of gaskets within said container, each gasket being directly supported on one of said annular ledge portions, indicator means within said container and tightly sandwiched between said gaskets; said indicator means comprising complementary half discs positioned in the same plane, one half disc being made of material whose color changes in response to spending of said gas filtering material and the other half disc being a reference of permanent color and of material unafiected by spending said gas filtering material, and a disc-shaped window supported by the gasket on said first mentioned annular ledge portion, said gaskets, and indicator means being tightly sandwiched by and between said ledge portions so as to form a gas-tight seal, whereby the remaining life of said filtering material may be visually observed through said window by comparing the colors of said half discs and whereby said canister may be readily removed from the outside of said canister by merely unsoldering and without breaking said seal.

2. A gas mask canister as recited in claim 1 wherein said gas filtering material is substantially hopcalite and said first mentioned half disc contains cobalt bromide in a suificiently small amount so as to substantially match the useful life of said hopcalite from the standpoint of moisture absorption and service life of the canister, for protection against carbon monoxide.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A GAS MASK CANISTER, A GAS FILTERING MATERIAL ENCLOSED THEREIN, THE WALL OF SAID CANISTER HAVING A CIRCULAR HOLE PUNCHED OUT THEREOF DEFINED BY AN INWARDLY BENT, PERIPHERAL PORTION, A SEAMLESS, METALLIC, SUBSTANTIALLY CYLINDRICAL CONTAINER OF DIAMETER SLIGHTLY SMALLER THAN THAT OF SAID HOLE, SNUGLY FITTED IN SAID HOLE, SAID CONTAINER HAVING, ON ONE SIDE, A RADIALLY OUTWARDLY FLARED, PERIPHERAL BEAD PORTION HAVING A TAPERED PORTION COMPLEMENTING AND SNUGLY SEATED IN SAID INWARDLY BENT PERIPHERAL PORTION AND BEING SOLDERED THERETO EXTERNALLY OF SAID CANISTER, SAID BEAD PORTION TERMINATING IN A RADIALLY INWARDLY BENT, ANNULAR LEDGE PORTION, THE OTHER SIDE OF SAID CONTAINER ALSO HAVING A RADIALLY INWARDLY BENT, ANNULAR LEDGE PORTION, A PAIR OF GASKETS WITHIN SAID CONTAINER, EACH GASKET BEING DIRECTLY SUPPORTED ON ONE OF SAID ANNULAR LEDGE PORTIONS, INDICATOR MEANS WITHIN SAID CONTAINER AND TIGHTLY SANDWICHED BETWEEN SAID GASKETS, SAID INDICATOR MEANS COMPRISING COMPLEMENTARY HALF DISCS POSITIONED IN THE SAME PLANE, ONE HALF DISC BEING MADE OF MATERIAL WHOSE COLOR CHANGES IN RESPONSE TO SPENDING OF SAID GAS FILTERING MATERIAL AND THE OTHER HALF DISC BEING A REFERENCE OF PERMANENT COLOR AND OF MATERIAL UNAFFECTED BY SPENDING SAID GAS FILTERING MATERIAL, AND A DISC-SHAPED WINDOW SUPPORTED BY THE GASKET ON SAID FIRST MENTIONED ANNULAR LEDGE PORTION, SAID GASKETS, AND INDICATOR MEANS BEING TIGHTLY SANDWICHED BY AND BETWEEN SAID LEDGE PORTIONS SO AS TO FORM A GAS-TIGHT SEAL, WHEREBY THE REMAINING LIFE OF SAID FILTERING MATERIAL MAY BE VISUALLY OBSERVED THROUGH SAID WINDOW BY COMPARING THE COLORS OF SAID HALF DISCS AND WHEREBY SAID CANISTER MAY BE READILY REMOVED FROM THE OUTSIDE OF SAD CANISTER BY MERELY UNSOLDERING AND WITHOUT BREAKING SAID SEAL. 